Liquid crystal display devices have been used for watches and electronic calculators, various measuring apparatuses, automotive panels, word processors, electronic notebooks, printers, computers, televisions, watches, advertising displays, etc. Typical examples of a liquid crystal display mode include a TN (twisted nematic) mode, a STN (super twisted nematic) mode, a vertical alignment mode and an IPS (in-plane switching) mode using TFT (thin-film transistor), and the like. Liquid crystal compositions used for these liquid crystal display devices are required to have stability to external stimuli such as moisture, air, heat, light, and the like, exhibit a liquid crystal phase within as wide a temperature range as possible including room temperature as a center, and have low viscosity and low drive voltage. Further, each of the liquid crystal compositions is composed of several types to several tens types of compounds in order to have optimum values of dielectric anisotropy (Δ∈) and/or refractive index anisotropy (Δn) for a display device.
A vertical alignment (VA)-mode display uses a liquid crystal composition having negative Δ∈, while a horizontal alignment-mode display, such as a TN mode, a STN mode, an IPS (in-plane switching) mode, or the like, uses a liquid crystal composition having positive Δ∈. Also, there has been reported a driving method in which a liquid crystal composition having positive Δ∈ is vertically aligned with no voltage applied, and display is performed by applying a transverse electric field, and the need for a liquid crystal composition having positive Δ∈ is further increased. On the other hand, low-voltage driving, fast response, and a wide operating temperature range are required for all driving methods. That is, a large absolute value of positive Δ∈, low viscosity (η), and a high nematic-isotropic liquid phase transition temperature (Tni) are required. Also, in view of setting of Δn×d which is the product of Δn and a cell gap (d), it is necessary to adjust Δn of a liquid crystal composition within a proper range according to the cell gap. In addition, when a liquid crystal display device is applied to a television or the like, fast response is regarded as important, and thus a liquid crystal composition having low rotational viscosity (γ1) is required.
A liquid crystal composition disclosed as a configuration of a fast response-oriented liquid crystal composition uses, for example, a compound represented by formulae (A-1) or (A-2), which is a liquid crystal compound having positive Δ∈, in combination with a liquid crystal compound (B) having neutral Δ∈. In the field of liquid crystal compositions, the liquid crystal composition is widely known to be characterized in that the liquid crystal compound having positive Δ∈ has a —CF2O structure, and the liquid crystal compound having neutral Δ∈ has an alkenyl group (Patent Literatures 1 to 4).

With expanding application of liquid crystal display devices, significant changes are found in use method and manufacturing method thereof. In order to cope with these changes, it is demanded to optimize characteristics other than basic physical property values which have been known. That is, VA-mode and IPS-mode liquid crystal display devices using liquid crystal compositions are widely used, and supersized liquid crystal devices of 50 inches or more are put into practical application. With increases in substrate size, instead of a usual vacuum injection method, a one drop fill (ODF) method becomes the mainstream of a method of injecting a liquid crystal composition into a substrate, but when a liquid crystal composition is dropped on a substrate, the problem of degrading display quality by dropping marks is surfaced. Further, in a process of manufacturing a liquid crystal display device by the ODF method, it is necessary to drop a liquid crystal in an optimum amount according to the size of a liquid crystal display device. A large deviation of the dropping amount from the optimum value disrupts a balance between previously designed refractive index and driving electric field of a liquid crystal display device and causes the occurrence of spots and display defects such as contrast defect and the like. In particular, small liquid crystal display devices in heavy use for recently popular smart phones have a small optimum amount of liquid crystal filling, and thus it is difficult to control a deviation from the optimum value within a predetermined range. Therefore, in order to maintain liquid crystal display devices in high yield, also required is, for example, the performance of being little influenced by a rapid pressure change and impact produced in a dropping apparatus during dropping of a liquid crystal, and being capable of continuous stable dropping of a liquid crystal over a long time.
Accordingly, for liquid crystal compositions used for active matrix drive liquid crystal display devices which are driven with TFT elements or the like, developments are being required in view of a method for manufacturing a liquid crystal display device in addition to the characteristic of having high resistivity or high voltage holding ratio, which has been regarded as important, and stability to external stimuli such as light, heat, and the like while maintaining the characteristics and performance, such as fast response and the like, which are required for liquid crystal display devices.